The present invention relates to a disposable diaper.
A disposable diaper comprises a water-permeable surface sheet, a water-impermeable back sheet and an absorbent material sandwiched therebetween. The urine absorption capacity of the disposable diaper depends on the volume of the absorbent material.
The urine absorption force of a disposable diaper must be high at the pubic region. In order to secure the high urine absorption force at the pubic region, a pubic region fitting portion of a prior-art disposable diaper has been broad.
However, such a disposable diaper with the broad pubic-region-fitting portion entails a drawback in that it makes it difficult or impossible to achieve a closeness of fit in the pubic region, and promotes leakage therefrom. That is, the broad pubic-region-fitting portion of the diaper causes a pocket-shaped space thereby producing a gap between the wearer and the diaper and causing urine to leak laterally from the diaper.
In an attempt to solve this problem workers in the art have selected the width of an absorbent material of the pubic region fitting portion to be 150-200 mm to improve closeness of fit to the pubic region. Other workers have attempted to improve the urine diffusivity through the thickness of the absorbent material. Still other workers have devised a disposable diaper which had a double pubic layer in an attempt to reduce the lateral urine leak.
However, so far these changes have not sufficiently prevented urine from leaking laterally from the diaper. In particular, it has been difficult to prevent urine from leaking laterally from the pubic region fitting portion when the wearer is lying on his or her side.